ML20084R148

Ro:Primary Containment Not Inerted to Less than 5 % Oxygen Content within 24-h of Placing Mode Switch Into Run.Caused by Late Arrival of Nitrogen Delivery

ML20084R148
Person / Time
Site:	Quad Cities
Issue date:	08/17/1973
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084R153	List: ML20084R148 ML20084R154
References
BBS-163, NUDOCS 8306140813
Download: ML20084R148 (2)

Text

C:mm:p:, ith Edison

..uclear Power Station

, I e MI Quad Citie .

s l Post Office Box 216 , ,

Cordova. Illinois 61242 9 '

l Tolephone 309/654-2241 .. p f W .?/ (7 BBS-163 August 17, 1973 -

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Mr. John ~F. O' Leary  ? 4 j. /

Directorate of Licensing .,. . ,;

U. 8. Atomic Energy Commission \ y y Washington, D. C. 20545 4r "#

SUBJECT:

Quad Cities Nuclear Power Station Unit 1 and 2, Docket # 50-254 ana 50-265 DPR-29 and DPR-30, Appendix A Section 1.0.A.2 and 3 7 5.b.

Dear Mr. O' Leary:

. The purpose of this letter is to inform you of the details which resulted in a situation whereby the Unit 1 primary containment was not inerted to less than 5% oxygen content within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of placing the mode switch into RUN. This occurrance was pre-viously reported by telegram on Aug. 7 at 4:30 p.m.

PROBLEM & INVESTIGATION _:

On August 4 & 5 both Quad Cities units were being brought back to power from cold shutdown. Unit 2 had been chutdown nearly eight days, while Unit 1 was down for approximately five days.

Unit 2 was made critical at 11: 48 p.m. on August 4 with Unit 1 going critical the following day at 7:33 p.m. As a result of the two unit startup both primary containments had to be inerted with nitrogen within less than a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period of each other.

The capacity of the on-site nitrogen storage tank, which was pre-viously filled on July 30, is not great enough to facilitate inerting the primary containment of both units. In anticipation of the dual startup the station ordered a load of nitrogen from Chemetron Corp., National Gas Division, on August 4 at approxi-mately 11:00 a.m. and loads were also ordered on August 6, 7, &

8. Chemetron made a commitment to deliver the nitrogen ordered on August 4 no later than 10 p.m. on August 6. Since Unit 1 was placed in the RUN code at 2:06 a.m. on August 6 the 10 p.m. de-levery would allow suficient time to inert Unit 1 within 24-hours.

However, the delivery did not arrive until 5: 00 a.m. on Aug. 7 1 and since the on-site supply of nitrogen in the storage tank was depleted while inerting Unit 2, Unit 1 could not be inerted with .

l in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

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O Mr. John F. O' Leary August 17, 1973

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, Upon arrival of the nitrogen, steps were taken to begin inerting the Unit 1 primary containment. At 8: 00 a.m. on August 7 inerting was begun and was discontinued at 2:00 p.m. when the nitrogen supply was depleted. At this point the.drywell oxygen content was down to k% with the torus content at approximately 10%. Gen-erally wne load of nitrogen is sufficient to completely inert one unit, however, the Standby Gas Treatment system was used to inert due to high activity in the drywell and more nitrogen was needed than normal. A second load of nitrogen arrived at 12: 30 a.m. on Au gu s t 8. Inerting of Unit 1 containnent was resumed at 3:45 a.m.

and by 8:30 a.m. the containment atmosphere oxygen concentration was at desired levels. Later deliveries of nitrogen served to re-plenish the nitrogen storage tank supply.

EVALUATION AND CORRECTIVE ACTION:

The Chemetron dispatcher was questioned about the late arrival of the nitragem delivery. His records revealed the truck had left Countryside, Ill. at 7: 00 p.m. on August 6. At 11:00 p.m. Just prior to leaving the Interstate highway to proceed to the station, the truck was stopped at the weigh scales for being overweight.

The truck was detained there for some time and therefore did not arrive at the station until 5:00 a.m. on August 7 The delay in inerting the primary containment does not have any significant safety implications since the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period is an arbitrarily determined time to allow for inspections and inerting.

Red it not been known that the arrival of nitrogen truck was immi-nent an orderly shutdown would have been initiated.

The on-site nitrogen supply is checked as a weekly surveillance item and is kept at a level high enough to allow inerting the pri-mary containment of at least one unit. Due to the nature of this two unit startup and the delay of the nitrogen delivery this occur-rence was unavoidable. This is the first occurrence of this nature at Quad-Cities and Chemetron Corporation has been informed of the urgency of our need for nitrogen in some situations. No further corrective actica is contemplated at this time.

Respectfully, c

B. B. Stephenson Station Superintendent BBS/jse ,

1 cc: Regional Director ,

Directorate of Regulatory Operations - Region III 4

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